Muffler for safety-valves



(No Model.)

H. G. ASHTON.

MUFFLER FOR SAFETY VALVES.

No. 299,503.- Patented June 3, 1884.

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UNITED STATES PATENT OFFICE.

HENRY G. ASHTON, OF SOMEBVILLE, MASSACHUSETTS.

MUFFLER FOR SAFETY-VALVES.

SPECIFICATION forming part of Letters Patent No. 299,503, dated June 3, 1884.

Application filed February 14, 1884. (N0 model.)

To all whom it may concern:

Be it known that I, HENRY G. ASHTON, of Somerville, in the county oflVIiddleseX and State, of Massachusetts, have invented a new and useful Improvement in Mufflers for Safety- Valves, of which the following is a specification.

My invention relates to improvements in safety-valves from which the steam escapes into a chamber having its outlet constructed by a device called a muffler, for preventing the noise accompanying the discharge of steam.

In all valves heretofore used with a muf fler, the muffler-chamber, into which the steam escapes from the valve, has surrounded thevalve, or been in such relation to the valve that the pressure of steam in the muffler-chamber has had an injurious effect upon the operation of the valve, by causing an additionalload, aiding the spring in closing the valve; and the object of my invention is to so combine the valve and the muffler-chamber that the steampressure in the muffler-chamber shall not affect the operation of the valve.

The accompanying drawing shows a safetyvalve and muffler on the dome of a locomotive, and illustrates my invention as embodied in the best form now known to me.

A is the steam dome of a locomotive, provided with the usual ornamental covering, a.

B is a safety-valve attached in the ordinary way.

D is the muffler-chamber, into which the steam that escapes through the valve B enters. The outlet from the chamber D is through a muffler, d, of any usual construction, generally of two perforated plates, (1 (1 with a packing of wire-gauze or the like between them. It is obvious that the escape of the steam must be so retarded by the muffler as to cause a pressure considerably above that of the atmosphere within the chamber D. This pressure in the chamber D acts on the valve when arranged as heretofore, and so increases the load on the valve as to cause it to slam down onto its seat, and as this prevents the entrance of more steam into the chamber D, the pressure therein falls almost instantly and the valve again rises and is again slammed onto its seat, and so on. This constant slamming has been a serious defect in muffled valves, as it not only injures the valves, but also prevents the proper relief of the boiler. To overcome these objections and to render a muffled valve as durable and as effective in relieving the boiler as any other, I have combined with themuffler-chamber D a valve fitted to and moving in a chamber, 1), and have connected this chamber 1) with the air outside of the muffler-chamber D by means of a pipe, b.

Any approved form of valve may be used, my invention not relating to the special form of valve, but to its combination with the muffler-chamber D, in which the steam is somewhatconfined by the muffler d, and with the valve-chamber b, which has connectionv with the atmosphere outside of the mufflerchamber D, so that the small quantity of steam which enters the valve-chamber Z) from the muffler-chamber D cannot create any material pressure in the valve-chamber b. In some valves steam is prevented from entering the chamber 12 by means of a packing or a diaphragm; but in these valves the air in the chamber b is expanded by the heat of the steam, and will increase the load on the valve unless the chamber 1) be open to the atmosphere, and therefore my invention is equally applicable to such valves.

In the drawing a pipe, I), forms the communication between the chamber 1) and the atmosphere. quantity of steam that finds its way into the chamber I) can escape noiselessly, any material pressure, whether from steam or expanded air, in the chamber 11 is prevented, and the upper side of the valve can be subjected to atmospheric pressure only. The outlet of the pipe I) should be so located as to prevent the entrance of cinders.

It will be obvious that the form of my ap- By means of this pipe the small,

paratus will vary largely, for every different Witnesses:

J. E. MAYNADIER, JOHN R. SNOW. 

